Over the weekend, we got to try out one of my favorite science demonstrations — the incredible shrinking styrofoam cups, a mainstay of sea-going oceanography. It’s a pretty amazing way to visualize the pressure that the ocean exerts at depth. It also results in a nice memento of the expedition — I’ve got a collection of shrunken cups from my previous cruises, as I know many of my fellow scientists do.
The way it works is simple. We all spend a day or two decorating cups with colored sharpies, then stuff them with paper towels (to help them maintain their shape as they shrunk) and pack them into a mesh bag. The bag gets zip-tied onto the CTD (more on the CTD here) before being lowered down to the bottom.
Most of our CTD “casts” only go down to about 1000 meters depth, because we are mainly interested in looking at plankton, who primarily reside near the ocean’s surface. But we are doing a couple of deep casts to the bottom of the ocean — in this case, 5100 meters, or more than 3 miles! These deep casts are perfect for a little demonstration of just how intense pressure can be.
In the crushing depths of the ocean, all of the air enveloped in the styrofoam gets forced out. When the cups resurface, they’re about one-third of their original heights! It always blows my mind to think about how much pressure these cups have been under — and then to think about the fact that all of our delicate equipment can withstand that same amount.
Decorating the cups was a fun distraction from the repetitive nature of running samples and filtering seawater. It also gave us a chance to show off our artistic sides and, as always, I was very impressed with the results. We had Hawaiian motifs, recalling our two-week hotel quarantine, many renditions of our ship, and an exotic variety of marine life. A few scientists experimented with cutting shark teeth or poking portholes in the cup as part of their designs, to great effect.
Yesterday was also a momentous day here on the Revelle. After all of our covid tests, quarantining, and social distancing, the ship has finally been determined to be covid-safe! At 12:00 midnight on the dot, we got to remove our masks and move within six feet of each other. I personally celebrated by giving as many hugs as I could when I got up in the morning. I’m definitely looking forward to spending the next 45 days mask-free!
Even though we’ve been gone from home for a very long time already, we’re still less than a third of the way through our cruise. We are firmly out of the sunny tropical waters that we’ve been enjoying for the last two weeks — as I’m writing this, we’re about to hit 40 °S and the ship is enveloped in a fog that makes me think I’m going to see the Black Pearl from Pirates of the Caribbean emerge at any second.
40 °S is also significant because it means we’re crossing into the latitudes known as the “Roaring Forties,” so named because the strong westerly, or east-flowing, winds here whip around the globe, almost unimpeded by land. This was an important region for shipping during the age of sail, but it’s also a region very prone to big storms, strong winds, and heavy seas. (The storms don’t stop at 50 °S, though — they just get called the “Furious Fifties” instead!)
It’s a reminder that despite the calm of the past two weeks, the weather in the ocean — particularly in the Southern Ocean — can change in an instant. On that note, I think I should go tie down some gear.
Giuliana Viglione is a journalist and science communicator who has joined Senior Research Scientist Barney Balch’s research cruise to study the impact of coccolithophores in the Southern Ocean. On board the ship, she’ll be helping the team carry out experiments, document the research cruise, and conduct educational outreach with students across the country. She can be reached at firstname.lastname@example.org.